Making zincs

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sail361

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Mar 21, 2009
19
Beneteau 361 Narragansett Bay,RI
Can anyone tell me if its possible to make your own zincs? I really don't like paying the crazy high cost of something so small and simple looking. I happen to have a Gori folding prop which does not allow me to go and pick them up at WM or such. I have to order them. The tail zinc isn't much bigger than a peanut and it doesn't last very long. I see 2 pound zincs at WM for a 1/4 of the price of mine. Is it safe to melt them down and mold your own, or is it toxic and unsafe and will the zinc lose it's protective qualities.
Keep in mind, I won't be inhaling the fumes during the liquifying stage. I did a sample melting on a small test piece, it didn't take alot of heat to do that.
Seemed to be around the same as solder. Should I forget this silly idea, and continue to wander around aimlessly looking for that rare piece of golden zinc shaped as none other?
Thanks in advance for your input.
Ed
 
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tommays

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Oct 2, 2006
1,517
Jboat J24 commack
Most of the cheep stuff is made of marginal alloy and has caused many a sterndrive powerboat to be dammaged
 
Tim R.

Tim R.

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May 27, 2004
3,626
Caliber 40 Long Range Cruiser Portland, Maine
The local WM does sell the cheap Chinese zincs.

Speaking of cheap, is your time really worth saving a couple of dollars?
 
G

Gary_H

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Nov 5, 2007
469
Cal 2-25 Carolina Beach NC
I would think it would not be worth all the effort to save a few bucks. I used to cast my own bullets and gave it up because It wasn't worth dealing with hot lead, burned fingers and swaging and lubing bullets when I could buy bulk precast for a few bucks.
 
Ross

Ross

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Jun 15, 2004
14,693
Islander/Wayfairer 30 sail number 25 Perryville,Md.
Zinc metal is currently selling at 73 cents per pound wholesale. Zinc melt at 790 degrees F. Therefore you could handle it with lead melting equipment. If you can make your patterns and properly flux the melt and safely pour 850 degree metal, then yes you could make your own anodes. I would buy the largest zinc anodes I could find and recast them to my needs.
 
Mike Holibar

Mike Holibar

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Jun 26, 2007
106
Freedom F39 Lyttelton New Zealand
Last year I looked at buying an anode manufacturing business that makes type approved (Lloyds Register of Shipping) anodes, both aluminium and zinc. I saw the manufacturing process and observed there are several "secret" ingredients, other than the base metal, that are added during the smelting process. This means the anodes are actually an alloy of different metals, and the best recipe gives the best anodes. This manufacturer poured the alloy into several different molds, one of which was in rod form about 5/8" dia. He gave me one of these which I cut and machined to fit the bronze plug which in turn, made up the heat exchanger anode. I simply heated the plug to melt out the last of the old anode, which revealed a thread cut into the plug. So I just had to screw the new rod into that. I would think twice about melting down a manufactured anode as I noticed tha other metals and trace elements were added at different temperatures in the process and reheating to the wrong temperature could spoil the mix, for want of a better term. While there are several manufacturers of anodes in NZ I note that the commercial shipping industry almost exclusively use these type approved anodes. Cheers,
 
BobM

BobM

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Jun 10, 2004
3,269
S2 9.2A Winthrop, MA
What you could do is set up a zinc recycling bin at your marina. I bet you could get enough old zincs to sell for scrap that your new one would be free!
 
Alan

Alan

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Jun 2, 2004
4,174
Hunter 35.5 LI, NY
I bough my shaft zinc from my local marina. It cost me $8.00. At prices like that I wouldn't even consider anything else. The zinc is made by Camp Co. St Petersburg, FL 33708. You may want to give them a call, (727) 397-6076
 
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MoonSailer

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Jun 7, 2007
875
Pearson- 323- Mobile,Al
I don't think that there is any "magic" involved in zincs. Should be easy to cast into almost any shape. Be sure if you recycle that there are no barnacles etc that could explode when heated. But I admit that my only experience is casting lead weights for my dive belt.
 
Ross

Ross

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Jun 15, 2004
14,693
Islander/Wayfairer 30 sail number 25 Perryville,Md.
Just don't drop dirty scrap into a melted pot! it is much worse than dropping an ICE Cube into a deep fat frier.
 
Ross

Ross

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Jun 15, 2004
14,693
Islander/Wayfairer 30 sail number 25 Perryville,Md.
My shaft zincs have a copper contact point in each half. I am not sure how it gets there but I am pretty sure that my very limited foundry skills couldn't make it happen.
 
S

sail361

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Mar 21, 2009
19
Beneteau 361 Narragansett Bay,RI
I wish the zinc for my prop only cost $8.00. There are actually 2 zincs, a very small one at the tail end, and a collar one at the head of the prop. There is no room for a shaft zinc (no exposed shaft). The collar zinc is about $65.00. I tried getting them from boatzincs.com. Only had the small one. Unfortunatley, they don't stock the collar zinc. So at $65.00 a pop, I was curious about home brewing them. I think my time would be well spent if I could get the mold down pat...
ED
 
M

MoonSailer

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Jun 7, 2007
875
Pearson- 323- Mobile,Al
Use a zinc "fish" while at the dock. This will help your expensive zincs to last longer.
 
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sail361

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Mar 21, 2009
19
Beneteau 361 Narragansett Bay,RI
Is it possible to over zinc and lose the protection they supply. I thought that I had heard it somewhere?
 
Mike Holibar

Mike Holibar

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Jun 26, 2007
106
Freedom F39 Lyttelton New Zealand
MoonSailer said:
I don't think that there is any "magic" involved in zincs. Should be easy to cast into almost any shape. Be sure if you recycle that there are no barnacles etc that could explode when heated. But I admit that my only experience is casting lead weights for my dive belt.
Click to expand
Zinc is as easy to cast as lead, but there is a little more involved in making a good anode. The Lloyd's surveyor was standing right beside me observing the manufacture of the type approved anodes, the addition of the other metals and trace elements was essential in producing an anode of the required quality.
 
Dan

Dan

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Jul 26, 2006
190
Hunter 420 Stamford
Yes, having too large or too many anodes is just as bad as not having enough.
Click to expand
Why is that, Sailingdog? How would you know if you're overzinc'd?

I use a zinc fish clipped to my engine. I assumed it was helping.
 
M

MoonSailer

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Jun 7, 2007
875
Pearson- 323- Mobile,Al
From Boatus.com


There is a common misconception that you can overprotect your drive by using too many zinc or sacrificial aluminum anodes. This is not true. The corrosion potential of any metal is a voltage that can be measured by a reference electrode. Such measurements in water commonly are made with a silver/silver chloride reference electrode. The corrosion potential of a sacrificial anode is a characteristic value for that metal, and it does matter if you have one piece of the metal or 100 pieces. The corrosion potential stays the same. Of course, 100 anodes would be expensive, heavy, and a considerable drag under water. Only by increasing the corrosion potential by using a different anode material (such as magnesium in seawater) can you overprotect your drive.

http://www.boatus.com/boattech/MarineCorrosion.htm
 
M

MoonSailer

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Jun 7, 2007
875
Pearson- 323- Mobile,Al
http://gulffishing.com/tips_anode.html

Here is another link. In short if you are using the right anode material for the conditions you can not overprotect. But if you use the wrong anode material you can overprotect. Magnesium in saltwater is overprotection. Zinc in freshwater is under protection. Aluminun alloy offers good protection in both fresh and salt water.
 
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